In a disc adapted for recording interleaved data thereon, data formed into clusters are recorded on the cluster basis in order to take data rewriting into account, as disclosed in, for example, JP Patent Kokai Publication No. 4-105271 or No. 4-301264.
As shown for example in FIG. 1, each cluster is constituted by a link sector and a data sector, and the length of the link sector is selected to be longer than an interleaving length. In this manner, each cluster is not affected by interleaving from neighboring clusters and recording and/or reproduction may be made independently on the cluster basis.
That is, with a disc on which data recorded thereon is interleaved data, data is recorded across plural sectors, without data being present independently on the sector basis. Consequently, rewriting of a particular sector cannot be performed by one operation and rewriting is to be performed on the cluster basis.
Meanwhile, in a disc recording apparatus in which data is grouped into clusters and recorded on the cluster basis, if data of the last cluster of main data for a writing 1 (first writing) is short of one full cluster, the portion of the cluster devoid of data is stuffed with void data to form one-cluster data and main data for the next writing 2 (second writing) is started with the next cluster. This indicates that a wasteful recording area 10 is produced as a result of stuffing the data free portion with void data.
Also, when rewriting data on the sector basis, data of the sector which belongs to the cluster to be rewritten and which is not rewritten has to be previously read out and combined with data which is to be rewritten and which is held on a random access memory. However, data readout needs to be made each time rewriting on the sector basis is performed, resulting in increased overhead until completion of recording.
In view of the above-described problems of the prior art, it is an object of the present invention to provide a disc recording apparatus in which the recording capacity of the disc may be fully utilized in carrying out recording, and in which accessing may be made expeditiously.